Process of uniting copper to steel



Oct. 7 1924.

J. B. AUSTIN PROCESS OF UNITING COPPER TO STEEL Filed Jan. 8, 1923 INVENTOR.

BY ,W+w1/z JOHN B. AUSTIN ms ATTORNEYS Patented Get. 7, 1924.

PATENT 0F? pan-5 JOHN B. AUSTIN, OF CLEVELAND, OHIO.

PRDCESS OF UNITING COPPER TO STEEL.

Application filed January 8, 1923.

T 0 all whom it may concern:

Be it known that I. JOHN B. AUSTIN, a citizen of the United States. residing at. Cleveland. in the county of Cuyahoga and State of Ohio, have invented a certain new and useful Improvement in Processes of Uniting Copper to Steel. of which the following is a specification.

This invention relates to the art of unitirig metals by cast welding. In particular it is concerned with a process of uniting copper to steel and the resulting product.

It is further concerned with the uniting of co per bonds to steel rails with an integr or alloyed junction throughout substantially the entire contacting surfaces of the copper and steei. It is also concerned with the provision of a process of uniting metals by cast welding with a substantially continuous and alloyed junction throughout the entire surfaces in contact and involving the use of a selective heat retaining and heat conducting mold for one of the metals.

It is further concerned with an electric arc process of cast Welding copper to steel, wherein one electrode of the arc is a mold for retaining molten copper or is molten copper itself. and the other electrode is (a) a carbon pencil, or (b) a rod of copper.

It also relates to a process of uniting copper to steel by which a. suitable reagent, such as silicon, is thoroughly disseminated throughout the molten metal under such conditions that the reagent comes in contact with and removes oxide material and gases in the copper and removes any oxide on the surface of the steel with which the molten copper comes in contact.

Broadly considered, my process consists in melting copper preferably by means of an electric are, so as to form a bath thereof in contact with steel and disseminating throu h the bath a quantity of a reagent capab e of removing oxides and gases from the molten bath, and either removing occluded gases therefrom or retaining them in solution after solidification of the metal, and also to remove any surface oxide from the steel. The copper is maintained at a temperature sufiiciently high and for a period of time sufiiciently long to cause the reagent to perform its functions and to cause the formation of what is believed to be Serial E0. 511,240.

an alloy film throughout the contacting sur' faces of the copper and steel.

Although I believe that the metals alloy with each other to form what appears to he an alloy film throughout their contacting surfaces, they may mutually penetrate into each other. Accordingly I do not wish to be understood as limiting my invention to alloying action of the metals. Vt'herever herein I employ the term alloy, alloy film, alloy junction or similar I sions, I refer to the connection forms tween the two metals whatever may be its nature or character provided it is a con nection similar to that produced by my process.

As will be mentioned hereinafter and also as mentioned in my copending application. Serial No. 610,347, filed January 3, 1923 the alloy film formed between and integrally connected to the two metals is characterized by being composed of fine-grained, highly ductile, dense. non-porous metal of high tensile strength. It is also free from sub stantially all gas cavities and slag inclusions or formations. The mechanical strength of its connection to the steel is greater than the tensile strength of the copper as is shown by the fact that efforts to separate the bond from the rail by shearing always cause a. rupture of the copper outside of the alloy film.

By the term reagent as employed in this application I mean any substance, element, compound or mixture, as metallic silicon, possessing the property of- (1) Reacting with occluded gases in the molten metal bath to prevent their escape therefrom or render them harmless by re t aining them in solution in the metal. as it solidifies,

(2) Reacting with any oxide in a molten metal bath to alter the form of the oxide and remove it therefrom,

(3) Reacting with any oxide on the surface of a metal in contact with a molten metal bath to alter the oxide and remove it, and

(4) Reacting with any gases in the molten metal adjacent the surface thereof to prevent their escape or render them harmless by retaining them in solution in the metal as it solidifies.

My invention in its broader aspects has been disclosed in my copending application F erial No. 610,347,filed January 2,1923. In this present application, however, I have chosen to disclose my invention as practiced in the electric arc procws of uniting copper to steel, particularly copper bonds to steel rails, and involving the use of a selective heat retaining and heat conducting mold for molten copper, either or both the mold or copper comprising one electrode of the arc, and (a) a carbon pencil, or (b) a copper rod comprising the other electrode of the are.

In the drawings attached hereto and forming a part of this specification,

Figure 1 is a top plan view of a railway rail to which is secured a copper bond and a mold adapted for use with my process.

Fig. 2 is a vertical cross-section taken substantially on line 22 of Fig. l, looking in the direction indicated by the arrows.

Fig. 3 is a cross-sectional view similar to Fig. 2 but showing a modified bond with the bond head completed and with the mold removed.

Figs. 4 and 5 are respectively top plan and vertical cross sectional views of a mold cavity representing the first step of my process.

Figs. 6 and 7 are views similar to Figs. 4 and 5 but representing an intermediate step in the process.

F' 8 and 9 are views similar to Figs. 47 inclusive, but showing the completed bond head.

I will now first describe my improved process with reference to the uniting of copper bonds to steel rails and involving the use of a carbon electrode and a selective heat retaining and heat conducting mold. No claim is made herein to the mold itself since I understand this mold to be the invention of Mr. Ly'rin S. Burgett of Cleveland, Ohio, and to be disclosed in his application for Letters -Patent Serial No. 617.988, filed February 9, 1923.

To one side of the rail designated by 1 a mold 2 is secured by any suitable means (not shown) after the terminal portion of a bond 3 has been positioned in a cavity, which may be called the casting cavity in the mold, so as to be flush with one ed e of the mold and thus contact with the rail. It will be obvious to those skilled in the art that a bond could be similarly positioned on the web or base of the rail instead of on the head of the rail, as here shown, if desired, it being only necessary to modify or alter in some respects the construction of the mold for these various locations as will be readily understood. It will thus be seen that whether a bond is being attached to the head, base or other part of a rail. the rail forms a portion of the retaining wall which serves to retain molten metal in contact with the copper of the bond.

\Vith the parts assembled as shown in Fig. 1 and the positive terminal of an electric circuit connectedto the rail, the negative terminal, which may be composed of various materials but preferably of carbon in pencil form, is brought into contact with the mold 2 and an arc is formed. Copper 12. preferably in rod form and containing a suitable reagent in proper amounts, is melted by the arc into the casting cavity 4 of mold 2, beginning at a point remote from the head of the bond, as shown in Fig. 4. The are is directed on the molten co per thereby maintainin the temperature 0 the same above the me ting point of the copper and, due to the well-known force of the arc, mechanically agitating the bath of molten metal. The flame of the arc is directed upon the surface of the molten bath without, however, being directed upon the rail until the bath has been heated to a sufficient temperature for the reagent therein to react on the combined oxides and occluded gases of the copper and the surface oxides of the rail and until the copper wets the rail. This condition and the completion of these reactions will be indicated y a ripple like movement on (the surface of the copper or a flowing away of what appears to be slag on the surface of the copper, at which time the surface of the copper as-. sulnes a concave form 13 resembling a me niscus adjacent to the rail. Additional rod metal, is then melted into the casting cavity 4 and caused to wet and unite with the cop per already therein and similarly to unite with the rail. This operation is continued until the copper which has been melted into the casting cavity and united to the rail has approximate] the same height as the por tion of the ond terminal which projects above the bottom of the casting cavity, at which time the arc and molten copper together cause a partial melting down of the bond terminal and a union thereof with the copper in the casting cavity and with the adjacent rail. Additional rod metal is then melted into the casting cavity and the operations re eated until abond head of the desired height and size is obtained and united to the rail.

A copper rod containing silicon in the amounts of from about 2% to about 3% substantially uniformly distributed therein has been found satisfactory I for this purpose. Other reagents, such as manganese or aluminum in proper amounts have also been found satisfactory for the purposes of my invention.

Although I prefer to incorporate the reagent in the copper rod, it may be added to the molten copper in the casting cavity by other means, such for example as incorporating it in the part of the bond which is melted in the mold or in any other suitable manner, provided that the reagent is thoroughly comingled and disseminated throughout the molten copper in a manner to permit the reagent to function as desired.

The selective heat retaining and heat conducting mold designated by 1 comprises a steel or iron shell 5, suitably slotted along its front edge and formed for reception of a bond terminal having a projection near the end thereof. Within the shell 5 a thin steel sheet 6 is ositioned to engage with the upper side of tlie projection near the end of the bond terminal. At one side of the bond opening in the members 5 and 6 a relatively heavy copper plate 7 is placed on member 6 to contact with the bond. Upon the other side of the bond opening thin carbon plates 8 are placed on member 6 which constitute about one-half the bottom of the casting cavities 4, which are formed b recesses cut in the edge of a relatively thick carbon plate 9, seated upon members 6, 7 and 8. In the mold shown in Fig. 1 a sliding member 10 composed of a relatively thick copper plate bent downwardly at its rear to engage with a spring 11, as shown. constitutes a part of the bottom of the casting cavity along the rear of the bond terminal. This slide is provided to accommodate bond terminals of various thicknesses.

It will be observed that the first step in my process is to melt a small amount of copper into the casting cavity and to unite the same to the rail at a point remote from the bond. This heats the mold to the desired temperature and permits the formation of an integral and alloyed junction between the copper and the rail, which is substantially continuous throughout the limits of the contacting surfaces of the two metals and is formed substantially without any intervening entrapped gases. Additional small increments of copper are melted and united to the rail in a similar manner. Due to the fact that relatively small amounts or thin layers of copper are melted and successively united to the steel, practically all danger of occlusion of gases between the surfaces of the copper and steel is eliminated. As the process is continued the bond end becomes preheated and contact of the arc therewith is required for a very brief period of time to melt and join the bond strands to each other and to the already molten copper. and to elevate the temperature of the molten copper to cause it to alloy with the steel. As the process is continued and the end of the bond is melted. the bond is heated to a temperature suitable for the formation of the desired alloyed junction between the metals. Any heat greatly in excess of the desired amount is withdrawn or conducted away by members 7 and 10 and SlliilClGl'tt heat is also removed from the bond by these members to prevent injury to the parts of the bond outside of the mold, or loss of the molten copper due to its running through the bottom of the mold.

It is thus possible to unite a copper bond to a steel rail with an alloyed junction throughout substantially all parts of the contacting surfaces of the copper and steel and without the presence between such surfaces of substantially any occluded gases, which condition is indicated by the presence of bubble-like cavities between the metals when solidified.

It will be observed that the alloying or uniting of the copper to the rail takes place while the copper is molten and in contactwith the rail and after all gases and oxides have been removed from the metals. The alloying or uniting is thus effected between clean metal surfaces in the absence of gases or an oxidizing atmosphere, thus permitting interpenetration of the clean metals under most advantageous circumstances. It is not desirable to melt any appreciable amount of the steel and this I have provided against by drawing an are between the mold or the metal therein and keeping it out of direct contact with the rail at all times. Preferably the steel is not affected in any way by this process except the surface portion thereof which is freed of its oxide and united with the copper.

Turning now to my process as practiced when the positive electrode is composed of a copper rod which preferably contains the desired amount of suitable reagent, substantially the same mold as has been described may be employed and assembled as shown in Fig. 1. The positive electrode consisting of a copper rod is brought into contact with the mold 2 and an arc is drawn between the rod and mold which causes the copper rod to melt. The molten copper is collected in the casting cavity 4 remote from the bond terminal and. after a quantity has been melted therein. the heat and force of the arc is played directly upon it until the copper wets and unites with the rail. as has been described in detail previously. Additional increments are addcd and similarly united until the copper has filled the mold to about the height of the bond end above the bottom of the casting cavity. at which time the bond terminal is melted down somewhat by the arc and united to the rail. Thereafter the bond head is built up to the desired size. as previously described.

Although in the process hereinbeforc dcscrihed in which the carbon electrode is em ployed. it is possible to dispensc with the selective heat retaining and heat conduciing mold, it is more difiicult to dispense with such a mold in this latter process where the carbon electrode has been placed by a copper ele trode,

Although I prefer to incorpo ate in the copper electrode the proper amount oi reagcnt. it will of course be obvious to those skilled in the art that any of the variou methods of disseminating the. reagent throughout the molten copper. as mentioned in the above. or other methods could he adopted without departing from the spirit and scope of my invention. llikewisemsarb ous reagents, such those already proposed. or other suitable reagents could be substituted for silicon without departing from the scope of invention.

By means of this process copper can b united to steel without melting an appreci able amount of steel or disadvantageously changing. so far as I am able to determine. the physical character thereof.

The exact temperature at which this process should be carried out and especially the temperature of the step of causing the copper to alloy or unite with the steel is not definitely known. but so far as can be determined from various pyrometric tests. it appears to he above the melting point of copper and somewhat below the melting point of cutectoid steel.

Furthermore it is to be understood that the particular forms of apparatus shown and described. and the particular procedure set forth, are presented for purposes of explanation and illustration and that variou modifications of said apparatus and procedure can be made without departing from my invention as defined in the appended claims.

What I claim is:

l. The process of uniting copper bonds to steel rails which comprises positioning a copper bond adjacent to a steel rail, confining the bond in a composite mold having carbon and copper parts in contact with the bond. melting copper into a casting cavity of the mold by means of an electric arc. commingling therewith a reagent capable of removing oxides from the copper and from the surface of the rail with which the copper contacts. heating the copper to a temperature at which the reagent may re move the said oxides. and maintaining the copper at such temperature until the reagent has removed the sa d oxides and the copper has united with the bond and rail.

The process of uniting a copper article to a steel article which comprises positioning th articles in contact with each other. surrounding the copper article on a plurality of sides with a selective heat retaining and heat condmting mold having a casting cavitv adjacent to the copper articl striking an electric arc. between the m ld and a movable electrode. melting copper into the casting cavity at a point remote from the said copper article, disseminating throughout the molten copper a re agent capable of removing oxides therefrom and from the adjacent surface of the steel article, heating the molten copper by the electric arc until the reagent: has removed any oxides from the molten copper and the adjacent contacting surface of the steel article and finally melting a portion of the copper article and causing it to unite with the molten copper in the said casting rarity and with the adjacent portions of the said steel article.

3. The process of uniting copper bonds to steel rails which comprises positioning a copper bond adjacent to a steel rail, confining the bond in a suitable mold having a casting cavity. striking an are between the said mold and a copper electrode, melting the copper electrode into the casting cavity at a point remote from the said bond, disseminating throughout the said molten copper a reagent capable of removing oxides from the molten copper and the surface of the steel rail in contact therewith, heating the molten copper until the reagent reacts with any oxides in the copper and on the rail. and the copper unites with the rail, melting a portion of the bond and causing it to unite with the molten copper in the casting cavity and alloy with the steel, and conducting excess heat away from the molten metal and bond.

4. The process of uniting copper bonds to steel rails which comprises positioning a copper bond adjacent to a steel rail, confining the bond in a suitable mold having a casting cavity of which the rail forms one wall, striking an are between the said mold and a suitable electrode, melting copper into said casting cavity by means of said electric arc. commingling with the molten copper a reagent capable of removing oxides from the opper and the surface of the rail with which the copper contacts. permitting the molten copper in contact with the thus cleaned rail surface to penetrate into the steel. melting the terminal of the bond in the casting cavity and continuing to disseminate throughout the copper bath therein a suitable reagent as aforesaid. and causing the bond terminal to unite with the molten copper in the casting cavity and with the adjacent portions of the steel rail.

5. The process of uniting copper bonds to steel rails which comprises forming a mold cavity about a portion of the copper of a copper bond to retain molten metal in contact with a rail. melting copper and heating it in said cavity above its melting point in the presence of a deoxidizing reagent by directing a flame upon the copper without directing the flame upon the rail. and maintaining the copper above its melting point until the copper unites with the bond and wets the rail, forming a clean, non-porous alloy junction between the copper and the rail throughout their contacting surfaces.

6. The process of uniting copper bonds to steel rails which comprises forming a suitable mold cavity about a portion of the copper of a copper bond to retain molten metal in contact with the rail, melting copper containing a deoxiding reagent into said cavity and in contact with the rail and melting the end of the bond, heating the molten metal in the mold to a temperature above the melting point of the copper without melting a substantial portion of the rail and until the copper Wets the rail and unites with the bond, forming a substantially non-porous junction between the copper and the rail throughout their contacting surfaces.

7. The process of uniting copper bonds to steel rails, which comprises forming a suitable mold cavity about a portion of the copper of a copper bond to retain molten metal in contact with the rail, melting by means of an electric arc copper containing a deoxidizing reagent into said cavity and in contact with the rail and melting the ends of the bonds by directing the arc thereon without directing it on the rail and heating the molten copper until the copper wets the rail and unites with the bond, forming a substantially non-porous junction between the copper and the rail throughout their contacting surfaces.

8. The process of uniting copper bonds to steel rails, which comprises forming a suitable mold cavity about a portion of the copper of a copper bond to retain molten metal in contact with the rail, striking an arc with a copper electrode, melting the copper electrode by the electric arc in the mold cavity, meltin the end of the bond and heating the mo ten metal in the mold by directing the arc thereon without directing the are on the rail, until the copper Wets the rail and unites with the bond, forming a substantially non-porous junction between the copper and the rail throughout their contactin surfaces.

9. e process of uniting copper bonds to steel rails which comprises forming a suitable mold cavity about a portion of the copper of a bond adjacent the rail, melting copper into the mo d cavity by means of a heating flame, commingling therewith a reagent capable of removing oxides from the copper and from the surface of the rail with which the copper contacts, heating the copper to a temperature at which the reagent may remove the said oxides, and maintaining the copper at such temperature until the 60 reagent has removed the said oxides and thp1 copper has united with the bond and ra 10. The process of uniting a copper article to a steel article which comprises forming a suitable mold cavity about the co per article adjacent to the steel article, me ting copper into the mold cavity by means of an electric are at a point remote from the said cop,- per article, disseminating throughout the molten copper a reagent capable of removing oxides therefrom and from the adjacent surface of the steel article. heating the molten copper by the electric arc until the reagent has removed any oxides from the mo ten copper and the adjacent contacting surface of the steel article and finally melting a portion of the copper article and causing it to unite with the molten copper in the said mold cavity and with the adjacent portions of the said steel article.

11. The process of uniting copper bond to steel rails which com prises forming a suitable mold cavity about a portion of the copper bond adjacent to the rail, striking an arc with a copper electrode, melting the copper electrode by the electric are into the mold cavity at a point remote from the said bond, disseminating throughout the said molten copper a reagent capable of removing oxides from the molten copper and the surface of the steel rail in contact therewith, heating the molten copper until the rea ent reacts with any oxides in the copper and on the rail, and the copper unites with the rail, and melting a portion of the bond and causing it to unite with the molten copper in the mold cavity and with the steel rail.

12. The process of uniting copper bonds to steel rails which comprises forming a suitable mold cavity, of which the rail forms one wall, about a portion of a copper bond adjacent to a stee rail, melting into said mold cavity by means of a heating flame copper containing a reagent capable of removing oxides from the copper and the surface of the rail with which the copper contacts, melting the terminal of the bond in the mold cavity and disseminating throu bout the molten copper of the bond a suitable reagent as aforesaid, and causing the bond terminal to unite with the molten copper in the mold cavity and with the adjacent portions of the steel rail.

In testimony whereof, I hereunto aflix my 115 signature.

JOHN B. AUSTIN. 

